A Word on Gettier Cases

Posted: May 20, 2020 in General Presup Issues
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Often presuppositionalists are construed as holding to the “Justified True Belief” model of knowledge. This leads pernicious unbelievers to jump to Gettier cases as attempted defeaters of presuppositional method. These cases are, it’s generally conceded, defeaters of JTB models, or, at the very least, demand JTB models be re-worked to avoid difficulty.

Epistemologists holding to a JTB model are often described as “internalists” in the literature since, to rationally justify a belief requires one to “internally” perform a calculation (or series of calculations) of a sort that satisfies justification criteria. Usually this calls for a series of deductive inferences.

However, the relevant authorities of Presuppositionalism have all (or, mostly all) suggested that Van Til’s Revelational Epistemology is *not* internalist. See John Frame’s “Doctrine of the Knowledge of God”. He directly tackles the question in one of the appendixes suggesting Revelational Epistemology is neither “internalist” nor “externalist”, rather, it’s a…”both / and.” Moreover, Bahnsen, in “Analysis” pg. 244, summarizes Van Til by suggesting that both immediate knowledge and rational knowledge (knowledge arrived at through internal reasoning processes), are limiting concepts of each other and both take place within the Christian worldview.

So given the “externalist” thrust of Revelational Epistemology, it’s not immediately clear how Gettier cases pose a serious problem. Indeed, in Bahnsen’s “Stated and Defended”, when addressed, (pg. 99), they’re brought up as difficulties, not for the Christian, but for unbelieving internalist philosophers. Additionally, Michael Butler addresses Gettier cases in his series of lectures on presuppositional apologetics (lecture 15), similarly waving them off as problems we can pose to unbelieving internalists.

Nevertheless, and in light of Van Til’s notion of how internal and external factors act as “limiting concepts”, and also in light of how presuppositionalism takes place within a polemical framework, many presuppositionalists stick to the JTB model while arguing, since, even on externalist epistemologies, propositions must be rationally-justified before being accepted by one’s debate opponent. The only way around this is for one’s debate opponent to agree that this or that proposition can simply be assumed, without argument, but if he’s willing to do that, the apologist only need assume the truth of Christianity, without argument.

Since apologetics deals with reasons, the giving of them and the analyzing of them, it seems safe to stick to the JTB model, if only polemically. Speaking from my own experience as an apologist, I’m only willing to go into the details of a Revalational Epistemology with my debate opponent once it is clearly established that he cannot escape global skepticism any other way. Otherwise, I hold to the JTB model when debating.

(Consider a practical illustration: If an unbeliever offers an assertion that is based on his sense perceptions, it does the apologist no good to grant that the assertion may count as actual knowledge, adding “…but only if we’re operating on the Christian worldview…” which tends to needlessly complicate the apologetics project at that point, giving the unbeliever temporary – though unjustified – license. Better to stick to the internalist project by demanding rational justification. If he accidentally appeals to the Christian worldview to justify himself, you’re done. If not, then don’t simply give it to him!).

So, Gettier is tentatively back on the menu, and a response ought to be offered…

Consider a typical Gettier case: a farmer looks out his window and sees, what he thinks, is a sheep in his pasture. Really, someone has placed a facsimile sheep out there as a prank. Accordingly, the farmer forms the belief there is a sheep in his pasture. Despite the ruse, however, there is, behind the facsimile, an actual sheep.

Recall JTB:

Belief: There is a sheep in the pasture.

Truth: In this hypothetical, it actually is true that there is a sheep in the pasture.

Justification: The justifying factor in the illustration is the farmer’s seeing a facsimile sheep.

This seems to be a situation where the farmer has justified, true, belief, that, nevertheless, does not intuitively seem like “knowledge” to most people, leading internalists to rework their formula, or give it up all together.

But why not simply say the justification wasn’t an actual justification? Most internalists wish to avoid this since it could, potentially, open them up to having to offer infinite (or near infinite) chains of inferences before successfully justifying any single belief. To see this in action, let’s render the farmer’s rationalization for his sheep-in-the-pasture belief as a deductive inference. It might look something like this, with a clear modus ponens where, if P then Q. P, therefore Q:

1 – If my sense perceptions are reliable*, then I am sensing a sheep in the pasture.

2 – My sense perceptions are reliable.

C: There is a sheep in the pasture.

(*”Reliable” here, includes all the relevant stipulations about acceptable degrees of error, as well as the belief that it implies successful conference of justification to perceptual beliefs).

But in normal debates, no one would take this argument to *actually* justify the conclusion. An interesting property of deductive arguments is that their conclusion is only as certain as their premises. And formal validity, alone, is not enough to successfully justify a conclusion. To confer justification, the argument must be truth-preserving. To clarify, especially for atheists who may object at this point, consider the same argument form, only with the variables swapped:

1 – If the Bible is a relevant authority on what does or doesn’t exist, then God exists.

2 – The Bible is a relevant authority on what does or does not exist.

C: God exists.

…but no atheist would accept that this argument justifies the concluding belief. While there may be pedantic objections to 1 (based on contentious arguments about Scriptural exegesis or some such), the serious and sustained criticisms will concern 2, specifically proving premise 2 is *actually true*.

Since this argument does not successfully confer justification onto the belief “God exists”, then neither does the farmer’s confer justification onto his belief “there is a sheep in the field” (regardless of the actual truth or falsity of the conclusion).

Two more deductive arguments are needed to provide rational justification for beliefs about propositions 1 and 2. But when the farmer attempts to provide a deductive argument for 1 – namely that “I am sensing a sheep in the pasture” – he will discover that proposition is false (once he discovers the ruse), and will realize his original belief (there is a sheep in the pasture) was unjustified, even if it was true.

The problem is that this requires an almost infinite number of deductive inferences. For every deductive argument offered, another deductive argument must accompany each of its premises.

This leads non-Christian philosophers to either accept skepticism or “lower the bar” of what counts as knowledge. We end up with some form of sociological epistemology, where, farmers, perhaps are only expected to have one or two deductive inferences to justify a belief. Lawyers and judges (in court) are expected to rely on many more. Scientists require more still and philosophers would require them all in a bid to find the end of the deductive chain (if one is to be found).

No philosopher can do this since it would require him to know *every* true proposition in order to ensure that they are all accounted for rationally.

It would require an omniscient mind…


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